Musnad Ahmad 1153:51

'Abd al-A'la narrated to us, from Ma'mar, from al-Zuhri, from 'Ubayd Allah ibn 'Abd Allah, from 'Abd Allah ibn 'Abbas and from 'A'ishah, that they both said: When the Messenger of Allah (peace and blessings of Allah be upon him) was overcome by death, he began to cast his *khamisah* (a garment) over his face. When he felt distressed, he would remove it from himself, while he was saying: "May Allah curse the Jews and the Christians; they took the graves of their prophets as places of worship." 'A'ishah said: "He was warning against the likes of what they did."